Convulsions in children immunized with a CSL Ltd. (CSL) flu shot probably were caused by an excessive immune response to viral components in the vaccine, according to preliminary findings of a two-year study. Use in children younger than 6 years of CSL’s Fluvax vaccine, to protect against the three main influenza strains circulating in the 2010 Southern Hemisphere winter, was suspended by Australian health officials in April of that year. Doctors reported a nine-fold increase in fever and convulsions in children following immunization with Fluvax.